Question: $2\dfrac{1}{5} \div \dfrac{4}{-9} = $
Let's start by converting the mixed number to a fraction. $\phantom{=}2\dfrac{1}{5} \div \dfrac{4}{-9}$ $=\dfrac{11}{5} \div \dfrac{4}{-9}$ $=\dfrac{11}{5} \cdot \dfrac{-9}{4}~~~~~~~\text{multiply by the reciprocal}$ $=\dfrac{-99}{20}$ $=-\dfrac{99}{20} \text{ or }-4\dfrac{19}{20}$